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Archiver > ALT-GENEALOGY > 1999-07 > 0931062683


From: Silver Bullet< >
Subject: Re: How many ancestors are possible?
Date: Sun, 04 Jul 1999 04:31:23 GMT


In the recent past, R. Craig Harman wrote:

>All of these analyses have been flawed by the fact that no estimation
>has been made of the importance of pedigree collapse in calculating
>ascendance. 1,024 ancestors at the tenth generation may work for a
>few people, but migratory patterns probably do not allow this. For
>someone whose ancestors remained sedentary -- my ancestors in two
>counties in SW Virginia over seven generations, for example, chances
>of pedigree collapse affecting the statistics are very high. And so
>far none of this analysis has even begun to accurately estimate this
>effect over the entire population nor begun to figure what the time
>dependance is (generations where famine or social forces cause diaspora
>etc.).

Actually I ** tried ** to account for this by applying the "cousin
dupes" discount. I meant cousin duplications to mean one physical
person occupying more than one "spot" in a descendancy, which is the
same thing as pedigree collapse.

I'll admit the estimates I used were completely and totally
unscientific and arbitrary. And... will vary a great deal from one
pedigree to another, particularly depending on how many cousin
marriages there were in a given pedigree early, say in the first four
generations. Because those early cousin marriages will "explode" in
numbers with each generation.

That said, I am kind of surprised that pedigree collapse hasn't
happened in my personal situation as much as I might have expected.
Out of 80 New England immigrants, I only have multiple lines of
descent (from a cousin marriage) in respect to two immigrant couples,
(two lines of descent in one case and four in another, ie two cousin
marriages). Out of meeting more than 100-200 cousins on the internet,
I am surprised how many I meet that are ** only ** related to me by
one ancestor. Considering the possibilities for intermarriages,
including particularly when the early families may have stayed in one
spot for awhile, I would have expected more folks related to me by one
ancestor to also be related to me by other ancestors.

But, that will be changing as time goes on and blood of those
20-30,000 New England immigrants continues to "spread" through the
population.

Norris

EMail: Norris Taylor <>
Most wanted this month: Corwin, Comstock, Purrier,
Osman, Swezey, Youngs, Penny, Cooper
Genealogy Home Page: http://members.aol.com/ntgen/index.htm

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